Emergency lighting units (ELUS) are used to illuminate residential and commercial facilities in the event of a power outage. Most ELUs are connected to an alternating current (AC) line power source during normal operation, and charge a battery to power the lighting unit when AC line power is interrupted for a significant period of time. These units are typically tested on a periodic basis to ensure that the battery is being sufficiently charged and that the ELU will operate during AC power failure. Testing generally entails activating a test instrument on the housing containing the emergency lighting fixture. This presents difficulties for human operators because the ELUs are generally located in inaccessible areas such as on the walls and ceilings of residential and commercial buildings. Thus, testing can be an arduous, time-consuming task for human operators, particularly when a large number of ELUs is present in an installation such as a warehouse.
A number of systems have been developed to facilitate testing of ELUs. For example, U.S. Pat. No. 5,148,158 discloses an ELU having a remote testing capability. The lighting fixture is provided in a housing which is mounted on a ceiling, for example, and which encloses circuitry for receiving radio frequency control signals from a hand-held transmitter. The remote test function commences when a button on the transmitter unit is depressed by an operator. The transmitter unit generates first and second radio frequency (RF) signals which, when received by the receiver circuitry, cause a bi-stable relay in the housing to interrupt and continue, respectively, the supply of line power to the lighting fixture. In another embodiment, the generation of a momentary RF signal initiates the test function, that is, disconnects the lighting fixture from the line power source for a predetermined period of time, and operates the lighting unit from a battery, before connecting the line power source once again.
U.S. Pat. No. 5,154,504 discloses an emergency lighting system comprising a portable control unit which communicates with each of several lighting units via a two-way, infrared communications link. The portable control unit comprises Start Test and Stop Test buttons to start and stop a test function, respectively, whereby the lighting unit is disconnected from a primary power source and operated from an alternate source.